Variable frequency heat pump intelligent control system based on sensorless vector control

Abstract

The application discloses a variable frequency heat pump intelligent regulation and control system based on sensorless vector control, belongs to the field of residential heating intelligent regulation and control, and comprises a sensorless vector control model construction and rotor state observation module, a temperature compensation and inductance parameter dynamic correction module and a compensation benchmark adaptive switching and iterative optimization module. The sensorless vector control model construction and rotor state observation module acquires three-phase stator voltage, current and inductance parameters of a compressor motor, constructs a sensorless vector control model for decoupling compressor motor torque and magnetic flux and eliminating parameter interference, realizes precise decoupling control of torque and magnetic flux by constructing the sensorless vector control model and combining Clark and Park coordinate transformation, effectively avoids frequent start and stop of the compressor under the defrosting condition, completely solves the problems of indoor heating interruption and abrupt drop of room temperature in the traditional defrosting mode, maintains stable indoor temperature, eliminates the uncomfortable feeling of hot and cold, and significantly improves the user experience in the low-temperature heating scene.

Description

Technical Field

[0001] This application belongs to the field of intelligent control of residential heating, and specifically relates to an intelligent control system for variable frequency heat pumps based on sensorless vector control. Background Technology

[0002] Variable frequency heat pumps are high-efficiency heating and cooling devices that achieve bidirectional heat transfer based on variable frequency technology and the heat pump cycle principle. Their core is to drive the refrigerant to change phase through the work of the compressor, thereby completing the heat transfer between low-temperature and high-temperature environments. They can achieve cooling or heating functions without directly generating heat or cold, and are widely used in various air conditioning systems.

[0003] During residential heating in winter, when the outdoor temperature is low and the air conditioner is running, water vapor in the air will frost up on the fins of the outdoor unit. When the fins are frosted, they will block the airflow channels, reducing the heat exchange area and efficiency of the air conditioner, affecting the heat exchange between indoors and outdoors, and thus reducing the indoor heating effect. In current technology, to avoid the reduction in the heat exchange between indoors and outdoors due to frost on the air conditioner fins, a reverse circulation is used to allow the high-temperature refrigerant to flow through the outdoor unit heat exchanger to melt the frost layer, while a defrosting fan is used to assist in defrosting.

[0004] However, when the air conditioner is in defrost mode, the indoor heating will be temporarily interrupted because the reverse circulation changes the flow direction of the refrigerant and the heat exchange function. During the defrosting process, the surface temperature of the outdoor unit's heat exchanger will fluctuate drastically as the frost melts. At this time, the air conditioner compressor will be in a state of frequent start-stop, which will cause the indoor heating to be temporarily interrupted, resulting in a sharp drop in indoor temperature. When the compressor restarts, the heating power needs to be increased again, which can easily lead to a slow recovery of indoor temperature.

[0005] Furthermore, frequent start-stop cycles of the compressor not only cause instantaneous fluctuations in current, disrupting the continuity of heating, but also subject the internal mechanical components of the compressor (such as bearings and valve plates) to repeated impact loads. Over time, this will exacerbate component wear and shorten the service life of the equipment.

[0006] Meanwhile, the instantaneous fluctuations in current will disrupt the control rhythm of the air conditioning control system, resulting in a significant decrease in heating effect. The low temperature and load fluctuation environment under defrosting conditions will further amplify the nonlinearity and strong coupling characteristics of the air conditioning control system, leading to inaccurate control parameters and exacerbating compressor instability.

[0007] Moreover, when the air conditioner is set to defrost mode, the internal temperature of the outdoor unit will change drastically due to factors such as heat absorption during defrosting of the fins and convection of cold air. This will cause the compressor motor parameters to drift, disrupt the magnetic coupling balance between the stator and rotor, and cause the compressor to start and stop frequently, which will further affect the indoor heating effect of the residence.

[0008] Therefore, to avoid the above situation, the present invention provides a variable frequency heat pump intelligent control system based on sensorless vector control. Summary of the Invention

[0009] To address the aforementioned issues, this application provides a variable frequency heat pump intelligent control system based on sensorless vector control.

[0010] A variable frequency heat pump intelligent control system based on sensorless vector control includes a sensorless vector control model construction and rotor state observation module, a temperature compensation and inductance parameter dynamic correction module, and a compensation benchmark adaptive switching and iterative optimization module.

[0011] The sensorless vector control model is constructed by acquiring the three-phase stator voltage and current of the compressor motor through the rotor state observation module, and obtaining the inductance parameters through the DC bias method to construct a sensorless vector control model for decoupling the compressor motor torque and flux linkage and eliminating parameter interference; the inductance parameters include rotor mutual inductance and rotor self-inductance.

[0012] Input the three-phase stator voltage and current to the sensorless vector control model, and output the compressor motor rotor position and the real-time speed of the motor rotor.

[0013] The temperature compensation and inductance parameter dynamic correction module calculates the motor winding resistance based on the motor stator phase voltage and phase current, and derives the real-time temperature of the motor winding.

[0014] Based on the real-time temperature of the motor windings, the internal temperature of the outdoor unit of the air conditioner is calculated as a temperature compensation benchmark; then the changes in rotor mutual inductance and rotor self-inductance are calculated to obtain new rotor mutual inductance and rotor self-inductance.

[0015] Input the new rotor mutual inductance and rotor self-inductance into the sensorless vector control model, and recalculate the rotor flux component, motor rotor position, and motor rotor real-time speed.

[0016] The adaptive switching and iterative optimization module for compensation benchmarks acquires the instantaneous deviation, sets the temperature threshold and the number of iterations threshold, compares the temperature threshold with the instantaneous deviation, outputs different types of temperature compensation benchmarks, and recalculates the rotor flux component, motor rotor position and real-time motor rotor speed again through the sensorless vector control model based on the different types of temperature compensation benchmarks.

[0017] Preferably, the sensorless vector control model construction in the rotor state observation module specifically involves:

[0018] Based on the three-phase stator voltage and current of the motor, a three-phase voltage balance equation is constructed to describe the dynamic balance relationship between stator voltage, current and flux linkage.

[0019] Using equal power transformation, a Clark transformation matrix is ​​constructed from three-phase to two-phase. The three-phase stator voltage and current are substituted into the Clark transformation matrix to calculate the α-axis components and β-axis components, and an α and β two-phase stationary coordinate system is constructed.

[0020] By using the orthogonal linear transformation of the Clark transformation matrix, the three-phase stator voltage and current are directly converted into two-phase stationary components in the α and β scale systems, thus removing the spatial coupling relationship of the three-phase windings.

[0021] The Park transformation converts the two-phase stationary components of the α and β coordinate systems into d and q rotating coordinate system components for decoupling control of flux linkage and torque.

[0022] Preferably, in the temperature compensation and inductance parameter dynamic correction module, the motor winding resistance is equal to the sum of the active power of the three-phase stator voltage and current, divided by the sum of the mean square values ​​of the three-phase stator current.

[0023] The real-time temperature of the motor winding is equal to the rated reference temperature plus the difference between the motor winding resistance and the motor winding resistance at the rated reference temperature, divided by the product of the resistance temperature coefficient of the copper winding and the winding resistance at the rated reference temperature.

[0024] The internal temperature of the outdoor unit of the air conditioner is equal to the real-time temperature of the motor windings plus the instantaneous deviation between the real-time temperature of the motor windings and the ambient temperature inside the outdoor unit, plus the real-time temperature of the motor windings.

[0025] Preferably, the temperature threshold rule set in the compensation benchmark adaptive switching and iterative optimization module is as follows:

[0026] Obtain the temperature coefficients of core permeability and permanent magnet remanent density corresponding to the mutual inductance and self-inductance of the motor rotor, and calculate the fluctuation amplitudes of the mutual inductance and self-inductance of the motor rotor as a function of temperature.

[0027] Obtain the fluctuation amplitudes corresponding to rotor mutual inductance and rotor self-inductance respectively, and then iteratively calculate the fluctuation amplitudes again;

[0028] Set an iteration count threshold, and stop iterating when the iteration count equals the iteration count threshold, and obtain the same number of fluctuation amplitudes as the iteration count threshold;

[0029] The maximum and minimum values ​​among multiple fluctuation ranges are used to form the temperature threshold. Specifically, the maximum value is the upper limit of the temperature threshold, and the minimum value is the lower limit of the temperature threshold.

[0030] Preferably, the iteration number threshold rule set in the compensation benchmark adaptive switching and iterative optimization module is as follows:

[0031] Samples of fluctuation amplitudes corresponding to different internal temperatures of the outdoor unit of the air conditioner are obtained. When the air conditioner is in defrost mode, the fluctuation period of the internal temperature of the outdoor unit of the air conditioner, as well as the sampling period of rotor mutual inductance and rotor self-inductance are obtained. The calculation result obtained by dividing the fluctuation period of the internal temperature of the outdoor unit of the air conditioner by the sampling period of rotor mutual inductance and rotor self-inductance is rounded up to the integer, thereby setting the threshold for the number of iterations.

[0032] Preferably, the comparison temperature threshold and instantaneous deviation in the compensation benchmark adaptive switching and iterative optimization module are as follows:

[0033] like If the temperature threshold is reached, the currently calculated internal temperature of the outdoor unit of the air conditioner will be used as the temperature compensation benchmark to recalculate the new rotor mutual inductance, rotor self-inductance, and rotor flux component.

[0034] Conversely, if the instantaneous deviation is less than or equal to the temperature threshold, the real-time temperature of the motor windings will be used as the temperature compensation benchmark again to recalculate the new rotor mutual inductance, rotor self-inductance, and rotor flux linkage components.

[0035] Preferably, the rotor flux linkage component is calculated in the sensorless vector control model as follows:

[0036] ;

[0037] in:

[0038] This refers to the stator winding resistance.

[0039] The rotor's electric angular velocity;

[0040] For mutual inductance between stator and rotor;

[0041] For rotor self-inductance;

[0042] , These are the components of the stator voltage in the α and β coordinate systems;

[0043] , These are the components of the stator current in the α and β coordinate systems;

[0044] For integration operators

[0045] Preferably, in the temperature compensation and inductance parameter dynamic correction module, based on the internal temperature of the outdoor unit of the air conditioner, the changes in rotor mutual inductance and rotor self-inductance in the sensorless vector control model are calculated as follows:

[0046] The new rotor mutual inductance is the rotor mutual inductance plus the change in rotor mutual inductance at the current internal temperature of the outdoor unit of the air conditioner.

[0047] The new rotor self-inductance is the rotor self-inductance plus the change in rotor self-inductance at the current internal temperature of the outdoor unit of the air conditioner.

[0048] Preferably, the change in rotor mutual inductance is: ;

[0049] The change in rotor self-inductance: ;

[0050] in, The temperature coefficient of magnetic permeability of the iron core. is the temperature coefficient of remanence density of a permanent magnet.

[0051] Preferably, the rotor flux linkage component is recalculated in the temperature compensation and inductance parameter dynamic correction module as follows:

[0052] ;

[0053] ;

[0054] in:

[0055] This represents the true value of the rotor's self-inductance under the current internal temperature of the outdoor unit of the air conditioner.

[0056] This represents the true value of the mutual inductance between the stator and rotor at the current internal temperature of the outdoor unit of the air conditioner.

[0057] For the self-sensing of the stator, , These are the stator flux linkage components in the α and β phase stationary coordinate systems, respectively;

[0058] , These are the stator current components in the α and β phase stationary coordinate systems, respectively.

[0059] Compared with the prior art, this application has the following advantages:

[0060] 1. By constructing a sensorless vector control model and combining Clark and Park coordinate transformations to achieve precise decoupling control of torque and flux, it can effectively avoid frequent compressor start-stop caused by the air conditioner being in defrost mode. It completely solves the problems of indoor heating interruption and precipitous drop in room temperature in traditional defrost mode, maintains stable indoor temperature, eliminates the discomfort of sudden temperature changes, and significantly improves the user experience in low-temperature heating scenarios.

[0061] 2. By collecting real-time data on the three-phase voltage and current of the motor, and dynamically correcting parameters such as rotor mutual inductance and rotor self-inductance that are deviated due to temperature drift, the rotor position and real-time speed can be accurately observed. This allows the compressor to operate stably under complex conditions such as load fluctuations and sudden temperature changes during the defrosting stage, avoiding instantaneous current fluctuations and repeated impacts on mechanical parts, reducing compressor wear, and extending the overall service life of the equipment.

[0062] 3. By reverse-engineering the real-time temperature of the motor windings and combining it with the instantaneous deviation, the internal temperature of the outdoor unit is accurately obtained, providing a reliable benchmark for parameter compensation. Furthermore, by dynamically updating the parameters of the sensorless vector control model, the interference caused by time-varying inductance, nonlinear coupling, and temperature drift generated in the sensorless vector control model is eliminated. This effectively improves the accuracy of the motor rotor torque output, optimizes the energy conversion efficiency of the compressor, reduces energy loss during the defrosting stage, and enhances the overall energy efficiency of the air conditioning control system.

[0063] 4. Temperature data and parameter drift information are indirectly obtained through motor voltage and current signals, eliminating the need for additional sensors, which simplifies hardware structure design and reduces costs. At the same time, the compensation benchmark is dynamically switched by judging the temperature threshold, which can adapt to complex conditions such as different wind speeds and frost thicknesses during defrosting, avoiding over- or under-compensation, and ensuring that the air conditioning control system can maintain high reliability and control accuracy in various extreme environments.

[0064] 5. By stabilizing the compressor's operating status, the high-temperature refrigerant is ensured to flow continuously and evenly through the outdoor unit's heat exchanger during the defrosting stage, improving the efficiency of frost melting and quickly restoring the heat exchanger's heat exchange capacity; at the same time, it avoids refrigerant pressure fluctuations caused by frequent compressor starts and stops, ensuring efficient heat exchange between indoors and outdoors and further enhancing the air conditioning's heating effect.

[0065] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0066] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0067] Figure 1 A schematic diagram of the working principle of a variable frequency heat pump intelligent control system based on sensorless vector control is shown.

[0068] Legend: 100, Sensorless vector control model construction and rotor state observation module; 200, Temperature compensation and dynamic correction of inductance parameters module; 300, Compensation benchmark adaptive switching and iterative optimization module. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0070] like Figure 1 As shown, the present invention provides a variable frequency heat pump intelligent control system based on sensorless vector control, including a sensorless vector control model construction and rotor state observation module 100, a temperature compensation and inductance parameter dynamic correction module 200, and a compensation benchmark adaptive switching and iterative optimization module 300.

[0071] The sensorless vector control model constructs a rotor state observation module 100 to acquire the three-phase stator voltage and current of the compressor motor, and obtains inductance parameters through a DC bias method to construct a sensorless vector control model for decoupling the compressor motor torque and flux linkage and eliminating parameter interference; the inductance parameters include rotor mutual inductance. Rotor self-inductance Specifically:

[0072] The DC bias method for obtaining inductor parameters is specifically as follows:

[0073] The inductance parameters can be separated by utilizing the equivalent circuit characteristics of a motor under DC excitation. When a DC voltage is applied to the stator winding, the equivalent circuit of the motor can be simplified to a series connection of a resistor and an inductor. Furthermore, since the rate of change of DC current is zero, the inductive reactance of the inductor is... The voltage drop measured at this point is mainly used to overcome the winding resistance. By controlling the change in current, and utilizing the inductor's opposition to the change in current, the inductance value can be indirectly measured.

[0074] Variable frequency heat pumps are high-efficiency heating and cooling devices that use variable frequency technology as the core drive and are based on the heat pump cycle principle (relying on the compressor to do work, driving the refrigerant to undergo phase change in four stages: compression, condensation, throttling, and evaporation) to achieve bidirectional heat transfer. Variable frequency heat pumps do not directly generate heat or cold, but can transfer heat from a low-temperature environment to a high-temperature environment (heating) and from a high-temperature environment to a low-temperature environment (cooling) by consuming a small amount of electrical energy.

[0075] For example, when the outdoor temperature is below 5℃, the surface temperature of the outdoor unit's heat exchanger (finned tube) will drop below 0℃ during air conditioning heating operation. If the air humidity is high (relative humidity > 60%), water vapor will frost on the fins. The lower the temperature and the higher the humidity, the faster the frost will form. In an environment of -5℃ and 80% humidity, the frost thickness may reach 2-3mm after 1 hour of operation. Furthermore, if insufficient airflow causes excessively high water vapor concentration in local areas of the heat exchanger, the frost formation process will be accelerated.

[0076] Therefore, when an air conditioner is in use, the temperature and humidity of the outside environment will cause frost to adhere to the surface of the fins of the outdoor unit due to the low temperature. The frost will block the airflow channels of the fins, reduce the heat exchange area and heat exchange efficiency of the heat exchanger, and prevent the cold outside air from efficiently completing the heat exchange between the indoor and outdoor environments, thus significantly reducing the indoor heating effect.

[0077] In current technology, to restore the heat exchanger's heat exchange capacity, the air conditioner automatically switches to defrost mode and works with the defrost fan in the outdoor unit to defrost the fins. For example, by using reverse circulation, high-temperature refrigerant flows through the outdoor unit's heat exchanger, using the refrigerant's heat to melt the frost layer. However, because the reverse circulation changes the refrigerant's flow direction and heat exchange function, indoor heating will be temporarily interrupted. Furthermore, during the fin defrosting process, the surface temperature of the outdoor unit's heat exchanger will fluctuate drastically as the frost layer melts. Traditional control systems need to frequently detect the frost layer status and heat exchange efficiency, which will cause the compressor to repeatedly adjust its operating power, resulting in the compressor frequently starting and stopping when the air conditioner is in defrost mode.

[0078] If the compressor starts and stops frequently, its motor operating conditions will change abruptly, resulting in frequent instantaneous fluctuations in current. For example, when the compressor starts, the motor needs to accelerate rapidly from a standstill to its operating speed. At this time, the starting torque required by the motor is much greater than the torque required during stable operation (the starting current is usually 5-8 times the rated current). When the compressor stops, the refrigerant will gradually reach pressure equilibrium on the high and low pressure sides (indoor / outdoor heat exchangers). However, at the moment of startup, the compressor suddenly starts to do work, which will quickly compress the refrigerant on the low pressure side into high pressure refrigerant, causing the pressure on the high pressure side of the motor to rise sharply and the pressure on the low pressure side to drop sharply, forming a pressure fluctuation in a short period of time.

[0079] The instantaneous fluctuation of current can disrupt the adjustment rhythm of the traditional control system, causing a significant decrease in heating efficiency and severely damaging the continuity of indoor heating. This results in a sharp drop in indoor temperature (typically, a single defrost will lower the room temperature by 2-3°C). Furthermore, the heating power needs to be increased again after the compressor restarts, and the room temperature recovers slowly, thus causing a significant deterioration in the user's heating experience. Especially in low-temperature and frigid environments, the indoor temperature will fluctuate, creating an uncomfortable state.

[0080] At the same time, frequent start-stop of the compressor will cause internal mechanical parts (such as bearings and valve plates) to be subjected to repeated impact loads. Over time, this will cause wear and tear on the compressor parts and ultimately shorten the equipment life.

[0081] Therefore, to avoid the above situation, the stator phase voltage of the compressor motor is obtained through sensors (voltage sensors, current sensors). Phase current A sensorless vector control model is constructed to decouple the compressor motor torque and flux linkage, and eliminate nonlinear coupling interference. This model accurately observes the motor rotor position and real-time rotor speed, thereby achieving stable compressor operation during the defrosting stage and avoiding frequent compressor start-stops. Specifically:

[0082] Because there is electromagnetic coupling between the stator windings and the rotor magnetic field of the compressor motor, the dynamic changes in voltage, current, and magnetic flux linkage follow the law of electromagnetic induction. Therefore, the phase voltage of the motor... With phase current As a core physical quantity describing the electromagnetic operating state of a motor, it ensures that the changes in voltage, current, and flux linkage of the motor satisfy the dynamic equilibrium relationship between Kirchhoff's laws and electromagnetic induction, thereby affecting the phase voltage of the motor. With phase current Establish the three-phase voltage balance equations in the ABC three-phase stationary coordinate system:

[0083] ;

[0084] in:

[0085] This refers to the phase resistance of the stator winding.

[0086] , , For the stator three-phase winding flux linkage;

[0087] For the stator winding flux linkages of phases A, B, and C , , The instantaneous rate of change over time;

[0088] However, since the stator windings of the compressor motor are fixed, while the rotor rotates continuously as the compressor runs, the spatial relative position of the stator windings and the rotor magnetic field changes periodically during this process (the relative position completes one cycle with each rotation). This change in the spatial relative position of the stator windings and the rotor magnetic field directly leads to the generation of time-varying inductance and electromagnetic coupling terms.

[0089] Time-varying inductance: Due to the periodic fluctuations in the relative position of the stator winding and the rotor magnetic pole, the degree of magnetic coupling between the two changes dynamically (the magnetic coupling is strong and the inductance is large when the rotor magnetic pole is directly opposite the stator winding, and the magnetic coupling is weak and the inductance is small when it is deviated).

[0090] Electromagnetic coupling: The electromagnetic quantities (voltage, current, flux linkage) of the stator and rotor are correlated due to the spatial interaction of the magnetic field (when the relative position changes, the degree of influence of the stator current on the rotor flux linkage and the voltage amplitude induced by the rotor magnetic field in the stator winding will change dynamically).

[0091] The generation of time-varying inductance and electromagnetic coupling terms will cause the sensorless vector control model to exhibit nonlinear and strongly coupled characteristics, thereby increasing the difficulty of designing and analyzing the sensorless vector control model. This makes it difficult to achieve precise decoupling control of the compressor motor speed and torque. Especially under low temperature and load fluctuation conditions during the defrosting stage, the control parameters are more likely to become inaccurate due to the characteristics of the sensorless vector control model, which will aggravate the frequent start and stop of the compressor and cause a deterioration in the indoor heating experience.

[0092] Therefore, to avoid the above situation, by adjusting the phase voltage... With phase current Perform Clark coordinate transformation to construct the α and β coordinate systems, specifically as follows:

[0093] Using equal power conversion, a three-phase to two-phase conversion matrix is ​​constructed, expressed as follows:

[0094] ;

[0095] Because the electric power of a motor is the core physical quantity describing its energy conversion state, coordinate transformation must ensure the consistency of energy characteristics so that the correspondence between the motor's voltage, current and power before and after the transformation is not distorted. Therefore, equal power transformation is adopted to construct a three-phase to two-phase Clark transformation matrix, which can ensure that the electric power of the air conditioning control system remains unchanged before and after the coordinate transformation, avoid introducing energy errors, and thus allow the transformed parameters to accurately reflect the actual operating state of the motor.

[0096] The Clark transformation matrix, constructed based on equal power transformation, has mutually orthogonal column vectors. This results in a linear transformation characteristic based on orthogonal axes, allowing the spatial coupling between the three-phase windings to be linearly stripped away. Therefore, the phase voltage... With phase current Substituting the values ​​into the Clark transformation matrix, we can calculate the α-axis and β-axis components, and construct α and β coordinate systems based on these components. The calculation expression is as follows:

[0097] ;

[0098] ;

[0099] Because the spatial coupling relationship of the three-phase windings of the motor is the core source of the nonlinearity and strong coupling characteristics of the sensorless vector control model, it makes it difficult for the sensorless vector control model to directly and independently adjust the real-time speed and torque of the motor rotor. This can lead to inaccurate control parameters during defrosting, resulting in reduced operating stability of the compressor motor. Therefore, by calculating the α-axis and β-axis components and constructing the α and β coordinate system, it is possible to ensure that the spatial coupling relationship between the three-phase windings can be linearly decoupled. This avoids the nonlinearity and strong coupling problems of the sensorless vector control model caused by time-varying inductance and electromagnetic coupling terms, thereby reducing the design complexity of the sensorless vector control system and laying the foundation for subsequent precise decoupling control of speed and torque. In particular, it can reduce the frequent start-stop of the compressor during the defrosting stage, avoiding the problems of decreased energy efficiency of the air conditioning control system and deterioration of the indoor heating experience.

[0100] Because the voltage and current in the three-phase stationary coordinate system are spatially coupled and exhibit periodic time-varying characteristics with rotor rotation, nonlinearity and strong coupling problems arise in the sensorless vector control model. This leads to decreased accuracy of the sensorless vector control and compressor instability during defrosting. Therefore, it is necessary to calculate the α-axis and β-axis components through orthogonal linear transformation of the Clark transformation matrix to output the voltage components in the α and β coordinate systems. , and current components , This makes the voltage components in the α and β coordinate systems... , and current components , It can perform subsequent Park coordinate transformations to further eliminate time-varying interference caused by rotor rotation, specifically:

[0101] The expression for calculating the orthogonal linear transformation of the Clark transformation matrix is ​​as follows:

[0102] ;

[0103] in:

[0104] , These are the instantaneous values ​​of the voltage components along the α and β axes in the α and β coordinate systems.

[0105] , These are the instantaneous values ​​of the current components along the α and β axes in the α and β coordinate systems.

[0106] Clark's transformation matrix, based on the linear transformation characteristics of orthogonal axes, transforms phase voltages... With phase current Substituting the Clark transformation matrix into the model allows the spatial coupling between the three-phase windings to be linearly stripped, thereby improving the analyzability and controllability of the sensorless vector control model and reducing the design and implementation difficulty of the sensorless vector control model.

[0107] Simultaneously, the α-axis components and β-components are calculated through orthogonal linear transformations of the matrix, and the voltage components in the α and β coordinate systems are output. , and current components , This not only avoids interference from time-varying inductance and electromagnetic coupling terms on the sensorless vector control model, but also isolates the spatial coupling relationship of the three-phase windings, simplifying the nonlinear and strongly coupled characteristics of the sensorless vector control model. This reduces the design complexity of the sensorless vector control model and improves its accuracy and stability. Especially under low temperature and load fluctuation conditions during the defrosting stage, it can effectively reduce the frequent start-stop of the compressor and improve the energy efficiency of the air conditioning control system and the indoor heating experience.

[0108] Furthermore, the present invention also considers that by adjusting the phase voltage... With phase current By performing Clark coordinate transformation and constructing α and β coordinate systems, the interference of time-varying inductance and electromagnetic coupling terms on the sensorless vector control model can be avoided. In addition, the spatial coupling relationship of the three-phase winding can be removed, which simplifies the nonlinear and strongly coupled characteristics of the sensorless vector control model and thus improves the indoor heating experience.

[0109] However, since the compressor motor rotor is in a state of continuous rotation when it is working, and the α and β coordinate systems are stationary coordinate systems, they cannot reflect the dynamic changes in the spatial position of the magnetic field caused by the rotor rotation. This will cause the sensorless vector control model to fail to accurately reflect the real-time coupling state of the stator and rotor magnetic fields. If the relative angle between the rotor magnetic poles and the stator windings changes continuously with the rotor rotation, the magnetic coupling strength between the stator windings and the rotor magnetic poles will exhibit periodic fluctuations, thereby causing the spatial relative position of the stator windings and the rotor magnetic poles to change periodically with the rotor rotation.

[0110] At this point, only the voltage components in the α and β coordinate systems are used. , and current components , The problem of time-varying inductance caused by rotor rotation and nonlinearity of the sensorless vector control model cannot be solved, which leads to a decrease in the accuracy of the sensorless vector control model, indirectly causing frequent compressor start-stop and reduced indoor heating effect.

[0111] Therefore, to solve the above problems, voltage components based on the α and β coordinate systems are used. , and current components , The α and β coordinate systems are transformed into d and q coordinate systems using Park coordinates, specifically as follows:

[0112] Since the voltage balance equation, based on Kirchhoff's laws, can directly describe the dynamic balance relationship between voltage, resistance voltage drop, and flux linkage rate, and since both the stator and rotor windings are in the same closed magnetic circuit, the magnetic fields generated by the stator and rotor windings will superimpose to form the total flux linkage acquired by the stator winding, i.e., the stator flux linkage (composed of the flux linkage generated by the stator current and the rotor flux linkage), therefore, based on the stator three-phase winding flux linkage in the voltage balance equation... , , Calculate the stator flux linkage components in the α and β coordinate systems. The specific expression is as follows:

[0113] Stator flux linkage components ;

[0114] Stator flux linkage components ;

[0115] in:

[0116] Stator flux linkage components It represents the projected component of the stator flux linkage on the α axis (which coincides with the axis of the A-phase winding), reflecting the magnetomotive force and magnetic flux distribution of the stator flux linkage in this direction;

[0117] Stator flux linkage components It represents the projected component of the stator flux linkage on the β axis (orthogonal to the α axis, leading the α axis by 90° electrical angle), reflecting the magnetomotive force and magnetic flux distribution of the stator flux linkage in the orthogonal direction;

[0118] Since the stator flux linkage is composed of the flux linkage generated by the stator current and the rotor flux linkage, the stator flux linkage equation is constructed based on the flux linkage coupling relationship between the stator and rotor of the motor. The rotor current is then obtained from the stator flux linkage equation and substituted into the stator flux linkage equation to obtain the rotor flux linkage component. , The expression is:

[0119] Rotor flux component ;

[0120] Rotor flux component ;

[0121] in:

[0122] The equivalent term for stator and rotor leakage inductance (known compressor motor parameters);

[0123] For mutual inductance between stator and rotor;

[0124] For rotor self-inductance;

[0125] Rotor flux component The component representing the projection of the rotor flux linkage on the α-axis (which coincides with the axis of the A-phase winding) reflects the magnetomotive force and magnetic flux distribution of the rotor magnetic field in this direction and is one of the key components for calculating the rotor flux linkage electric angle θe.

[0126] Rotor flux component It represents the projected component of the rotor flux linkage on the β axis (orthogonal to the α axis, leading the α axis by 90° electrical angle), reflecting the magnetomotive force and magnetic flux distribution of the rotor magnetic field in the orthogonal direction, and together with ψαr, constitutes the vector representation of the rotor flux linkage;

[0127] Furthermore, since the rotor current is obtained from the stator flux linkage equation, substituting it into this equation is problematic because the rotor windings are embedded inside the motor, making it impossible to directly deploy current sensors. This results in the current signal not being directly extracted for detection, reducing the feasibility of directly observing the rotor current. Therefore, the rotor current is a physical quantity that cannot be directly measured. Moreover, during motor operation, winding heating and load changes can cause magnetic circuit saturation and temperature drift. Motor parameters (such as inductance) will drift with temperature and magnetic circuit saturation, leading to a mismatch between the flux linkage observation model and the actual motor characteristics, ultimately affecting the rotor flux linkage component. , It is impossible to measure directly with sensors, and because the dynamic changes in rotor flux linkage are strongly coupled with motor speed and stator / rotor current, cumulative errors will occur between the observed and true values ​​of flux linkage. Therefore, the rotor flux linkage component... , Dynamic changes are coupled with motor speed and stator / rotor current, making accurate measurement impossible and ultimately causing traditional direct measurement methods to fail under dynamic operating conditions.

[0128] However, due to the time-varying nature of motor parameters and the occurrence of nonlinear disturbances in coupling terms, if traditional direct algebraic solutions or open-loop observation methods are used to solve the rotor flux linkage components... , Calculations may also lead to the divergence of observation accuracy over time and the lag in dynamic response, ultimately affecting the stability of torque output and speed regulation performance of motor vector control.

[0129] Therefore, the rotor flux component is calculated by integration. , This can avoid the direct accumulation of parameter disturbances and coupling errors, improve the robustness and dynamic tracking accuracy of rotor flux observation, and enhance the rotor flux component. , The specific expression is as follows:

[0130] ;

[0131] in:

[0132] This refers to the stator winding resistance.

[0133] The rotor's electric angular velocity;

[0134] For mutual inductance between stator and rotor;

[0135] For rotor self-inductance;

[0136] , These are the components of the stator voltage in the α and β coordinate systems;

[0137] , These are the components of the stator current in the α and β coordinate systems;

[0138] This is the integration operator;

[0139] At this point, the rotor flux component is calculated by time-domain integration based on the stator voltage, current, and flux coupling terms. , This not only smooths out instantaneous disturbances and suppresses the linear amplification of errors over time, preventing the direct accumulation of observation biases caused by parameter drift and nonlinear coupling, but also improves the dynamic response speed and anti-interference capability of flux linkage observation, ultimately enabling the rotor flux linkage component to... , It can achieve stable tracking of the real flux linkage under wide speed range and variable load conditions, avoiding the divergence of flux linkage observations and the failure of vector control decoupling.

[0140] Furthermore, since the rotor flux linkage is a spatial rotating vector whose direction changes dynamically with the operation of the motor, it will cause the rotor flux linkage component to... , The spatial angle changes dynamically, therefore it is based on the rotor flux component. , The rotor flux electrical angle is calculated using the inverse tangent function. The expression is as follows:

[0141] ;

[0142] However, due to the rotor flux electrical angle When used only for static orientation or low-speed operation, issues such as phase lag in the angle signal and insufficient dynamic tracking capability arise. This leads to insufficient response speed and decreased dynamic adjustment accuracy in subsequent speed closed-loop control, resulting in large torque fluctuations and poor speed stability during high-speed motor operation. Therefore, it is necessary to use an angle-based control system based on rotor flux electrical angle. Calculate the rotor electric angular velocity This causes the rotor's electric angular velocity to Capable of tracking rotor flux components in real time , The dynamic rotational speed provides a high-bandwidth dynamic feedback signal for the real-time speed closed-loop control of the motor, thereby improving the response speed of the subsequent real-time speed closed-loop control of the motor, improving the dynamic adjustment accuracy, and increasing the rotor electric angular velocity. The specific expression is:

[0143] ;

[0144] Because of the rotor's electric angular velocity The rate of change of the electrical angle is not directly equal to the mechanical speed of the motor, even if the rotor electrical angular velocity can be obtained. This improves the response speed of the subsequent real-time speed closed-loop control of the motor and enhances the dynamic adjustment accuracy.

[0145] However, due to the difference between the mechanical speed of the motor and the electrical angular velocity of the rotor... There is also a conversion relationship between pole pairs, and there is a lack of a reference for the absolute position of the rotor, making it impossible to directly obtain the real-time speed of the motor rotor, which represents the mechanical operating state. This will cause a mismatch between the reference of the speed closed-loop control and the actual mechanical speed, resulting in insufficient steady-state accuracy;

[0146] The rotor electric angular velocity is calculated by integration. To obtain the current position of the compressor motor rotor. The specific expression is:

[0147] ;

[0148] in:

[0149] for The mechanical position of the motor rotor at any given moment;

[0150] This represents the initial mechanical position of the motor rotor.

[0151] Based on the compressor motor rotor position and rotor electric angular velocity The differential relationship is used to obtain the real-time rotor speed of the motor, which represents the actual mechanical operating speed. The expression is:

[0152] ;

[0153] In summary, by measuring the rotor's electrical angular velocity... Perform differentiation and integration operations to output the motor rotor position. and the real-time speed of the motor rotor This enables the air conditioning control system to accurately track the dynamic motion of the rotor, thereby improving the response speed and dynamic adjustment accuracy of the speed closed-loop control. It not only enhances the torque output stability of the compressor motor and the energy efficiency of the air conditioning control system, but also optimizes the comfort and reliability of indoor heating. It can avoid frequent compressor start-stop, energy efficiency reduction and heating effect fluctuations caused by insufficient precision of the air conditioning control system.

[0154] Furthermore, by measuring the rotor's electrical angular velocity... Perform differentiation and integration operations to output the motor rotor position. and the real-time speed of the motor rotor Afterwards, since the air conditioner is in defrost mode, if the compressor experiences drastic load fluctuations or changes in the real-time speed of the motor rotor, Sudden changes in rotational speed can alter the motor's magnetic circuit saturation and parameters, thereby affecting the rotor flux linkage components. , The accuracy of the calculation;

[0155] Furthermore, when the rotor flux component , After the calculation accuracy decreases, due to the rotor flux electrical angle With rotor flux component , The inverse tangent function relationship will also directly affect the rotor flux electrical angle. Phase lag and rotor electric angular velocity Errors in calculations ultimately affect the position of the motor rotor. and the real-time speed of the motor rotor The accuracy of the calculations is insufficient to fully resolve the issues of time-varying inductance and nonlinear coupling.

[0156] Meanwhile, since the α and β coordinate systems are stationary, when the motor rotor rotates, the projection of the motor rotor magnetic field onto the α and β coordinate systems changes with time, manifesting as an AC component. This generates a dynamic coupling effect between the stator and rotor magnetic fields, leading to time-varying inductance and nonlinear coupling terms in the sensorless vector control model. During the air conditioner defrosting process, due to the drastic fluctuations in compressor load and the real-time speed of the motor rotor... The abrupt change will further amplify the time-varying inductance and nonlinear coupling terms, affecting the rotor flux linkage electrical angle. With rotor flux component , The impact will deepen further;

[0157] Therefore, to resolve the above situation, the voltage components in the α and β coordinate systems are... , Current components , Substituting these values ​​into the Park coordinate transformation matrix, the voltage and current components in the d and q coordinate systems are output. This effectively solves the time-varying inductance and nonlinear coupling problems caused by rotor rotation, achieving independent decoupling control of torque and flux linkage. This improves the accuracy and stability of the air conditioning control system under complex conditions such as defrosting. The specific expression is as follows:

[0158] ;

[0159] in:

[0160] The voltage component along the d-axis;

[0161] This refers to the q-axis voltage component.

[0162] ;

[0163] in:

[0164] The current component is the d-axis component;

[0165] This refers to the q-axis current component.

[0166] By using the voltage components in the α and β coordinate systems , Current components , Voltage components converted to d, q coordinate system , Current components , (This represents converting the AC components in the α and β coordinate systems that change periodically with rotor rotation into components related to rotor flux linkage.) , (DC component in synchronously rotating d, q coordinate system); It can simplify the original AC sensorless vector control model, which is affected by time-varying inductance and nonlinear coupling interference, into a decoupled control model of DC motor, thereby completely eliminating the problems of time-varying inductance and nonlinear coupling in the sensorless vector control model. It can not only improve the response speed and control accuracy of the compressor motor in the defrosting condition of the air conditioning control system, but also optimize the energy conversion efficiency of the compressor and the overall energy efficiency of the air conditioning control system. It can not only avoid the compressor motor torque fluctuation and speed instability in complex conditions such as defrosting, but also avoid the problem of frequent start-stop of the air conditioner in defrosting mode.

[0167] Furthermore, this invention fully considers that the rotational motion of the compressor motor rotor can directly change the spatial distribution and dynamic characteristics of the stator and rotor flux linkages. Therefore, the stator and rotor flux linkages can directly reflect the rotor motion state. By constructing an α and β coordinate system and combining it with the stator flux linkage equation, the spatial coupling relationship between the three-phase windings of the motor can be removed, thereby simplifying the nonlinear characteristics of the sensorless vector control model. Therefore, by calculating the rotor flux linkage components... , Capable of accurately observing the rotor flux electrical angle This solves the problem of insufficient decoupling control precision of compressor motor speed and torque in air conditioner defrosting mode, thereby improving the control stability of compressor motor under defrosting conditions, avoiding frequent start-stop due to speed inaccuracy, and improving the energy efficiency of variable frequency heat pump and the continuity of indoor heating.

[0168] However, when the air conditioner is in defrosting mode, it heats the fins with high-temperature refrigerant in reverse circulation to achieve defrosting. Since the fins are installed in the core heat exchange area on the air intake side of the outdoor unit and are in a continuous heat absorption state during the defrosting process, they will continuously absorb the heat carried by the high-temperature refrigerant and the heat around the fins, which will cause the internal temperature of the outdoor unit to drop.

[0169] When the temperature inside the outdoor unit of the air conditioner drops, the low-temperature environment inside the unit will change the mutual inductance between the stator and rotor of the motor. Rotor self-inductance On the one hand, it will cause the remanent magnet density of the permanent magnet to decrease as the temperature decreases, which will also cause the rotor magnetic field strength to decrease synchronously, affecting the stable operation of the compressor motor in defrosting mode, thus causing an imbalance in the coupling matching relationship between the stator and rotor magnetic flux.

[0170] On the other hand, it will cause fluctuations in the core permeability and changes in winding resistance, disrupting the magnetic coupling balance between the stator and rotor, thereby affecting the mutual inductance between the stator and rotor of the motor. Rotor self-inductance Parameters such as these lead to mutual inductance between the stator and rotor. Rotor self-inductance These parameters can deviate due to the internal temperature of the outdoor unit of the air conditioner, causing variations in the rotor flux component. , The calculation deviation is large and the calculation accuracy is reduced, which leads to a decrease in the rotor flux electrical angle. The observed values ​​exhibit phase lag and numerical deviation, making it impossible to accurately calculate the motor rotor position. and the real-time speed of the motor rotor This leads to problems such as decreased control accuracy of the sensorless vector control model and unstable operation of the compressor motor.

[0171] Therefore, to avoid the above situation, the temperature compensation and inductance parameter dynamic correction module 200 is based on the motor stator phase voltage. With phase current Calculate the internal temperature of the outdoor unit of the air conditioner. ;

[0172] And based on the internal temperature of the air conditioner outdoor unit The mutual inductance between the ground and rotor in the sensorless vector control model construction and rotor state observation module 100 is calculated. Rotor self-inductance The change yields the new rotor mutual inductance and rotor self-inductance.

[0173] And based on the new rotor mutual inductance and rotor self-inductance Recalculate rotor flux components , This corrects the position of the motor rotor. and the real-time speed of the motor rotor , specifically:

[0174] Obtain the motor stator phase voltage in the sensorless vector control model construction and rotor state observation module 100. With phase current Calculate the resistance of the motor windings The specific expression is:

[0175] ;

[0176] Because the compressor motor is a three-phase asynchronous motor with symmetrical three-phase stator windings and consistent electrical characteristics, its back electromotive force is negligible during defrosting startup or low-speed operation. The stator voltage is mainly used to overcome the voltage drop across the winding resistance. Therefore, by calculating the sum of the ratios between the three-phase voltages and currents, and then calculating the arithmetic mean of these ratios, the motor winding resistance can be calculated. This allows us to demonstrate the dynamic change characteristics of the motor winding resistance with temperature, enabling us to deduce the real-time temperature of the motor winding based on the resistance-temperature correlation formula. This, in turn, accurately characterizes the real-time temperature inside the outdoor unit of the air conditioner, providing a basis for temperature compensation for the sensorless vector control system and avoiding frequent compressor start-stop due to parameter drift during defrosting.

[0177] Because the resistance of copper motor windings has a strict linear positive correlation with temperature (due to the physical laws governing the resistance and temperature of metallic conductors). ,in: Rated reference temperature The winding resistance below, The temperature coefficient of resistance of copper has extremely high stability and repeatability. Furthermore, the resistance value of copper motor windings is not affected by external variables such as refrigerant pressure and frost thickness during defrosting conditions. It is determined solely by the winding temperature itself, which can provide a sufficient physical basis for temperature inference.

[0178] Furthermore, since the linear relationship between the resistance and temperature of copper only holds true within a specific temperature range and operating conditions, lattice scattering, impurity scattering, or back EMF interference outside this range can disrupt the linearity, potentially leading to deviations in the resistance-temperature relationship and increased discrepancies between calculated and actual temperatures. Therefore, operating condition constraints are necessary to ensure the validity of the linear relationship between resistance and temperature, and to guarantee that the accuracy and reliability of the temperature back-calculation meet system requirements. The specific operating condition constraints are as follows:

[0179] Temperature range: -10℃~50℃ (typical temperature fluctuation range of the outdoor unit under defrosting conditions, in which lattice vibration scattering is dominant and the influence of impurity / defect scattering is negligible).

[0180] Motor operating status: During the defrosting stage, the compressor runs at low speed (speed ≤1500rpm) or in a start-stop transition state. The back electromotive force is negligible, and the stator voltage is mainly used to overcome the voltage drop of the winding resistance.

[0181] Winding material: Industrial-grade oxygen-free copper winding (impurity content ≤0.1%), conforming to GB / T5231-2022 standard "Grades and Chemical Composition of Processed Copper and Copper Alloys".

[0182] Because of the synergistic effect of the aforementioned operating conditions and the linear physical laws governing the resistance and temperature of the copper windings, the influence of external interference and nonlinear factors can be eliminated, and the mapping relationship between resistance and temperature can be stabilized. This significantly improves the accuracy and robustness of the temperature back-calculation. At this point, the real-time temperature of the motor windings can be accurately deduced using the resistance-temperature correlation formula, eliminating the need for additional temperature sensors. This not only reduces system hardware costs and wiring complexity but also improves the real-time performance and anti-interference capability of temperature detection. Therefore, based on the resistance-temperature correlation formula, the real-time temperature of the motor windings can be calculated. The specific expression is as follows:

[0183] ;

[0184] in:

[0185] The rated reference temperature;

[0186] Rated reference temperature The resistance of the motor windings below;

[0187] The temperature coefficient of resistance of the copper winding;

[0188] It needs to be explained that the temperature coefficient of resistance of copper windings These are not fixed, universal values, but rather personalized calibration values ​​for specific compressor motors. Specifically, copper winding samples from the same batch and material as mass-produced compressor motors are selected. Three sets of winding wires of the same length (L=10cm) and cross-sectional area (S=1mm²) are cut. The samples are placed in a high-precision constant-temperature chamber, and temperature points are set sequentially. Using a high-precision micro-ohmmeter (measurement accuracy ≤±0.01μΩ), the resistance value of the sample at each temperature point is measured. Based on Matisse's law, considering the constant resistance component Rimp due to impurity / defect scattering, a corrected resistance model is established. ;

[0189] in:

[0190] The lattice scattering resistance at absolute zero;

[0191] It is a second-order temperature coefficient;

[0192] At this time, the temperature coefficient of resistance of the copper winding After simplification, linearization, and calculation, the specific expression is as follows:

[0193] ;

[0194] Because the resistance of the copper windings exhibits a strictly linear positive correlation with temperature, and because this correlation is unaffected by external disturbances such as refrigerant pressure and frost thickness during defrosting, the method of inversely calculating the real-time motor winding temperature using the resistance-temperature correlation formula possesses extremely high stability and reliability. This improves the temperature compensation accuracy of sensorless vector control systems. Furthermore, the method of using the motor winding resistance... Subtract the rated reference temperature motor winding resistance Divide by the temperature coefficient of resistance of the copper winding Multiply by the rated reference temperature motor winding resistance The ratio can accurately deduce the motor winding resistance. Real-time temperature This lays the foundation for improving subsequent estimations of the real-time temperature inside the outdoor unit of the air conditioner;

[0195] Although the real-time temperature of the motor windings can be calculated based on the formula relating resistance and temperature, However, because the compressor motor itself generates Joule heat during operation, and the high-temperature refrigerant flowing through the motor housing during the defrosting stage brings additional heat exchange, the real-time temperature of the motor windings will increase. There is a momentary deviation between the temperature of the motor windings and the internal ambient temperature of the outdoor unit, which affects the real-time temperature of the motor windings. It cannot directly display the internal temperature of the outdoor unit of the air conditioner;

[0196] At the same time, due to the stator phase voltage of the motor With phase current With motor winding resistance Directly related, while the motor winding resistance And also the real-time temperature of the motor windings The relationship is linear. The compressor motor also serves as the core heat-generating component of the outdoor unit, and it is installed in the central area inside the outdoor unit, directly exchanging heat with the air inside the unit through convection. When the air conditioner is running in defrost mode, the real-time temperature of the motor windings... The response will be synchronized with the internal temperature of the outdoor unit of the air conditioner, thereby ensuring the real-time temperature of the motor windings. The instantaneous deviation between the outdoor unit temperature and the internal temperature of the air conditioner is stable within ±1℃. Therefore, combined with the real-time temperature of the motor windings... and the real-time temperature of the motor windings The instantaneous deviation between the outdoor unit's internal temperature and the ambient temperature inside the outdoor unit allows for the estimation of the air conditioner's internal temperature. The specific expression is as follows:

[0197] ;

[0198] in:

[0199] Real-time temperature of motor windings Instantaneous deviation from the internal ambient temperature of the outdoor unit;

[0200] Because the compressor operates under stable load and refrigerant circulation flow is controlled during the defrosting phase, a dynamic balance is maintained between the Joule heat of the motor and the heat exchange power of the refrigerant. Therefore, the Joule heat power of the compressor motor and the refrigerant heat exchange rate during defrosting are relatively stable during system operation. Furthermore, because the difference between the winding temperature and the ambient temperature of the outdoor unit can be approximated as constant under this equilibrium state, if the instantaneous deviation... As a fixed compensation value, the real-time temperature of the motor windings is used. Subtract the instantaneous deviation of the indoor ambient temperature of the outdoor unit The internal temperature of the outdoor unit of the air conditioner is obtained. Subsequently, this effectively eliminates the interference from the motor's self-heating and restores the true ambient temperature, improving the accuracy and representativeness of temperature detection. This precisely offsets the temperature deviation caused by the motor's own heating and the additional heat exchange with the refrigerant, thus enabling accurate estimation of the internal temperature of the air conditioner's outdoor unit. ;

[0201] And due to rotor mutual inductance Rotor self-inductance The inductance parameters are highly sensitive to permeability and remanence, determined by both the core magnetic circuit and the permanent magnet magnetic field. Therefore, the rotor mutual inductance... Rotor self-inductance The magnetic permeability of the iron core and the remanent magnetization of the permanent magnet are strongly correlated. However, due to the linear changes in the magnetic domain thermal disturbance of the iron core and the thermal demagnetization effect of the permanent magnet with temperature, the magnetic permeability of the iron core and the remanent magnetization of the permanent magnet will change with the internal temperature of the air conditioner outdoor unit. If a linear change occurs, directly using the inductance parameters at room temperature for flux linkage observation may cause a deviation between the observed and actual flux linkage values, and failure of vector control decoupling. Therefore, the internal temperature of the air conditioner outdoor unit may change. It can directly reflect the mutual inductance of the rotor. Rotor self-inductance The dynamic changes in inductance parameters make temperature compensation more real-time and targeted, improve the robustness of flux linkage observation, and thus reduce the internal temperature of the air conditioner outdoor unit. It can serve as a dynamic temperature compensation reference for sensorless vector control systems, not only correcting inductance parameter errors caused by temperature drift, but also improving the accuracy of rotor flux observation and system operation stability under defrosting conditions.

[0202] For the reasons mentioned above, the temperature inside the outdoor unit of the air conditioner is used as a reference. Accurately calculate the current internal temperature of the outdoor unit of the air conditioner. Corresponding rotor mutual inductance Rotor self-inductance The change in temperature can not only quantify the impact of temperature on inductance parameters, thus providing a basis for subsequent accurate calculation of rotor flux components, but also... , It provides a basis for deviation and also enables dynamic online correction of inductance parameters, improving the rotor flux observation's resistance to temperature drift and the stability of vector control. Therefore, by establishing the current internal temperature of the air conditioner outdoor unit... A linear correlation model between the iron core's permeability and the permanent magnet's remanence can accurately calculate the current internal temperature of the air conditioner's outdoor unit. Corresponding rotor mutual inductance Rotor self-inductance The corresponding change is expressed as follows:

[0203] The change in rotor mutual inductance is: ;

[0204] The change in rotor self-inductance is: ;

[0205] in:

[0206] The temperature coefficient of magnetic permeability of the iron core;

[0207] The temperature coefficient of remanence density of a permanent magnet;

[0208] The change in rotor mutual inductance represents the current internal temperature of the outdoor unit of the air conditioner. Below, rotor mutual inductance Relative to the rated reference temperature The offset of the reference value reflects the influence of the combined change of the core permeability and the remanent magnet density on the magnetic coupling capability of the stator and rotor.

[0209] This is the change in rotor self-inductance, representing the current internal temperature of the outdoor unit of the air conditioner. Below, rotor self-inductance Relative to the rated reference temperature The offset of the reference value reflects the influence of the change in the core permeability on the flux linkage of the rotor winding itself.

[0210] Because a quantization model that maps temperature variables to inductance parameter offsets can accurately characterize the influence of temperature on magnetic circuit properties, it is possible to calculate the current internal temperature of the air conditioner outdoor unit. Corresponding rotor mutual inductance Rotor self-inductance The corresponding changes not only provide parameters for real-time correction of the rotor flux observation equation, but also allow for early prediction of the impact of parameter drift on control performance. This effectively suppresses temperature disturbances and eliminates flux observation errors, enabling the sensorless vector control system to maintain accurate decoupling and stable output under defrosting temperature conditions, thereby improving the compressor's operational stability and the reliability of the air conditioning defrosting process.

[0211] However, because the reference values ​​of inductance parameters and temperature offsets need to be used together in flux linkage calculations, and the offsets alone cannot reproduce the true magnetic circuit coupling characteristics, a mismatch will occur between the flux linkage observation equations and the actual motor physical model. Furthermore, due to rotor mutual inductance... Rotor self-inductance Corresponding change , Relative to the rated reference temperature Lower rotor mutual inductance Rotor self-inductance The offset can only represent the rotor mutual inductance. Rotor self-inductance The offset magnitude, rather than the actual inductance value, is used in this case if the rotor mutual inductance is used directly. Rotor self-inductance The change in value is used as the actual inductance value for the rotor flux component. , Performing calculations will not only lead to the inability to accurately calculate the rotor flux component, but also... , This causes the rotor flux linkage component , Current outdoor unit temperature of the air conditioner The calculated values ​​under the given conditions are inaccurate and will also affect subsequent calculations of the motor rotor position. and the real-time speed of the motor rotor As a result, the stability and control accuracy of the sensorless vector control system are reduced, therefore, the rotor flux component... , It depends more on the current internal temperature of the outdoor unit of the air conditioner. The calculation is performed using the actual inductance value, specifically:

[0212] Obtaining the change Change And the rotor mutual inductance in the sensorless vector control model construction and rotor state observation module 100 Rotor self-inductance Because the reference inductance value and temperature offset can be linearly superimposed to restore the true magnetic circuit parameters, the matching degree and physical consistency between the inductance parameters and the current operating temperature can be improved. Therefore, the current internal temperature of the air conditioner outdoor unit can be accurately calculated using the above parameters. The actual inductance value below (i.e., the new rotor mutual inductance in the temperature compensation and inductance parameter dynamic correction module 200) Rotor self-inductance The specific expression is:

[0213] ;

[0214] ;

[0215] in:

[0216] The current internal temperature of the outdoor unit of the air conditioner Below, rotor mutual inductance Rotor self-inductance The corresponding actual inductance value;

[0217] Because of the change , It is a precise offset value calculated based on temperature characteristics, which can reflect the current internal temperature of the outdoor unit of the air conditioner. The dynamic drift amplitude of the lower inductance relative to the reference value is considered. Therefore, the sensorless vector control model is constructed in conjunction with the rotor mutual inductance in the rotor state observation module 100. Rotor self-inductance Add change Change Output the current internal temperature of the outdoor unit of the air conditioner. Lower actual inductance value , It can not only accurately correct the instantaneous error caused by temperature drift, but also effectively improve the stability and control efficiency of the sensorless vector control system under defrosting conditions.

[0218] Because of the current temperature inside the outdoor unit of the air conditioner The actual inductance value calculated below , It already possesses sufficient capabilities based on material temperature characteristics and precise offset correction, thus fully reflecting the current internal temperature of the air conditioner's outdoor unit. mutual inductance of rotors and rotor self-inductance The effect can represent the current internal temperature of the outdoor unit of the air conditioner. The actual electromagnetic coupling characteristics under these conditions, at which point the actual inductance value will be... , As input parameters, these are re-inputted into the sensorless vector control model to calculate the current internal temperature of the outdoor unit of the air conditioner. The rotor flux component below , This allows the calculation results of the flux linkage components to better reflect actual working conditions, thereby improving the sensorless vector control system's ability to accurately determine the rotor position of the motor. and the real-time speed of the motor rotor The accuracy of observation;

[0219] Therefore, the stator flux linkage equation in the sensorless vector control model construction and rotor state observation module 100 is obtained, and the actual inductance value is... , As input parameters, these are re-inputted into the stator flux linkage equation to obtain the current internal temperature of the outdoor unit of the air conditioner in the α and β coordinate systems. Recalculated rotor flux component , The specific expression is:

[0220] ;

[0221] ;

[0222] in:

[0223] The current internal temperature of the outdoor unit of the air conditioner The actual inductance value;

[0224] , This refers to the stator current component;

[0225] , This refers to the rotor current component;

[0226] Stator current components , With rotor current component , Obtained from the sensorless vector control model in the rotor state observation module 100;

[0227] Because of the rotor flux component , Compared with the actual inductance value , Stator current components , With rotor current component , They are linearly coupled, and at this point, based on the actual inductance value... , The established flux linkage calculation relationship can then accurately map the effect of temperature deviation on the rotor flux linkage component. , The impact;

[0228] Therefore, the actual inductance value , Stator current components , With rotor current component , As input parameters, recalculate the current internal temperature of the outdoor unit of the air conditioner. The rotor flux component below , This results in the rotor flux component , This more closely reflects actual working conditions, improving the observation accuracy of the sensorless vector control system and facilitating subsequent calculations of the motor rotor position. and the real-time speed of the motor rotor It is more reliable and can also enhance the stability of the sensorless vector control model under defrosting conditions, and improve the accuracy of variable frequency heat pump regulation.

[0229] However, a further consideration of this invention is that when the air conditioner is in the defrosting stage, the internal temperature of the outdoor unit is... The temperature inside the outdoor unit of the air conditioner will decrease due to the heat absorption during defrosting of the fins and the combined effect of the convection between the outside cold air and the defrosting fan. It will be lost quickly, thus causing mutual inductance between the motor rotor and rotor. Rotor self-inductance Instantaneous fluctuations occur, thus affecting the rotor flux linkage component. , The accuracy of the calculations affects the final output of the motor rotor position. and the real-time speed of the motor rotor Deviation occurred;

[0230] Although at this time it is possible to use the temperature compensation and inductance parameter dynamic correction module 200 based on the mutual inductance of the motor rotor... Rotor self-inductance The change is dynamically corrected to calculate the current internal temperature of the outdoor unit of the air conditioner. The actual inductance value , However, if there is no wind outside (i.e., the cold air from outside does not combine with the cold air from the defrost fan), the internal temperature of the outdoor unit of the air conditioner will be... The temperature will only decrease due to heat absorption during defrosting of the fins, affecting the internal temperature of the outdoor unit of the air conditioner. The factors will change from multiple elements to a single element, while the internal temperature of the air conditioner outdoor unit, which serves as the temperature compensation benchmark, will change. Numerical deviations can lead to inaccurate calculations of the actual inductance value. , Sometimes, temperature compensation becomes excessive, deviating significantly from actual operating conditions. If, in this situation, the temperature compensation is still relied upon along with the actual inductance value from the dynamic inductance parameter correction module 200, then... , Calculate rotor flux components , This will cause the rotor flux component observed by the sensorless vector control model to be... , The mismatch with the actual electromagnetic characteristics leads to the rotor flux linkage component. , A significant deviation between the calculated and actual values ​​ultimately affects the motor rotor position. and the real-time speed of the motor rotor Deviations can affect the stability of the variable frequency heat pump's compressor control, resulting in insufficient regulation of the compressor motor. This causes the compressor to start and stop frequently during defrosting, leading to a sharp drop in indoor temperature.

[0231] Therefore, to address the aforementioned issues, the compensation benchmark adaptive switching and iterative optimization module 300 acquires the instantaneous deviation. Set a temperature threshold and an iteration number threshold, and compare the temperature threshold with the instantaneous deviation. Output different types of temperature compensation benchmarks, and recalculate the rotor flux linkage components based on these benchmarks. , and the position of the motor rotor and the real-time speed of the motor rotor Specifically:

[0232] Although combined with the real-time temperature of the motor windings and the real-time temperature of the motor windings Instantaneous deviation from the internal ambient temperature of the outdoor unit It can estimate the internal temperature of the outdoor unit of the air conditioner. However, if there is no wind or the wind speed is low outside, the internal temperature of the air conditioner's outdoor unit will be... The heat reduction effect due to the defrosting of the fins is even more pronounced, i.e., the real-time temperature of the motor windings. Instantaneous deviation from the internal ambient temperature of the outdoor unit This will decrease, thereby reducing the real-time temperature of the motor windings. Real-time temperature of motor windings The impact is increasing;

[0233] At the same time, the internal temperature of the air conditioner outdoor unit is monitored. The calculation formula can be used to determine the internal temperature of the outdoor unit of the air conditioner. Equal to the real-time temperature of the motor windings Plus the real-time temperature of the motor windings Instantaneous deviation from the internal ambient temperature of the outdoor unit Calculations show that, therefore, the internal temperature of the outdoor unit of the air conditioner is the temperature compensation reference at this time. It will also decrease when calculating the rotor flux linkage component later. , At the same time, it will also reduce the rotor flux component. , Calculate the deviation;

[0234] Therefore, a temperature threshold is set, and the temperature threshold is compared with the instantaneous deviation. ,like >Temperature threshold indicates the current internal temperature of the outdoor unit of the air conditioner. During calculation, it will be subject to instantaneous deviations. Real-time temperature of motor windings The influence of this necessitates the use of the rotor flux component in the temperature compensation and inductance parameter dynamic correction module 200. , The calculation logic will use the currently calculated internal temperature of the outdoor unit of the air conditioner. As a temperature compensation benchmark, the actual inductance value is recalculated. , To ensure accurate calculation of rotor flux components in subsequent operations , Improve the control accuracy of sensorless vector control systems;

[0235] Conversely, if there is an instantaneous deviation ≤Temperature threshold indicates the current internal temperature of the outdoor unit of the air conditioner. During the calculation, the real-time temperature of the motor windings is taken into account. The impact is greater than the instantaneous deviation The effect is that, at this time, the heat inside the outdoor unit of the air conditioner cannot be largely carried away by the convection generated by the outside cold air and the defrost fan, indicating that the temperature inside the outdoor unit of the air conditioner is low. Subject to the real-time temperature of the motor windings The impact is significant, therefore the rotor flux component in the temperature compensation and inductance parameter dynamic correction module 200 is used again. , The calculation logic calculates the real-time temperature of the motor windings. As a temperature compensation benchmark, the actual inductance value is recalculated. , and rotor flux component , It can greatly This reduces the computational complexity and load of the temperature compensation and inductance parameter dynamic correction module 200, avoids frequent switching of the temperature compensation reference which could cause oscillations in the sensorless vector control system, and also ensures the rotor flux component. , The accuracy of the observation ensures the precise calculation of the motor rotor position in the subsequent process. and the real-time speed of the motor rotor .

[0236] The temperature threshold setting rules are as follows:

[0237] Due to the mutual inductance between the motor rotor Rotor self-inductance The temperature will change non-linearly with temperature, and the heat dissipation efficiency of the outdoor unit of the air conditioner is affected by operating conditions such as wind speed and refrigerant state. If the temperature threshold setting deviates from the mutual inductance of the motor rotor... Rotor self-inductance The parameter characteristics can cause a mismatch between the temperature compensation benchmark and the actual operating conditions, thereby reducing the accuracy of motor control;

[0238] Therefore, obtaining the mutual inductance of the motor rotor Rotor self-inductance The corresponding temperature coefficient of magnetic permeability of the iron core Temperature coefficient of remanence of permanent magnets At this time, the rated reference temperature The motor rotor mutual inductance Rotor self-inductance The mutual inductance of the motor rotor is calculated by combining electromagnetic parameters and temperature coupling model. Rotor self-inductance The critical range that varies with temperature is specifically:

[0239] Because the temperature sensitivity of the core permeability and the remanence of the permanent magnet differs, and the proportions of domain thermal disturbance and thermal demagnetization effects vary across different temperature ranges, fitting and predicting the inductance parameter variation with temperature using an electromagnetic parameter-temperature coupling model can identify the critical inflection point and stable range of the inductance parameter variation with temperature. This effectively improves the targeting and effectiveness of inductance parameter temperature compensation. Therefore, by using the rated reference temperature... The motor rotor mutual inductance Rotor self-inductance The mutual inductance of the motor rotor is calculated by combining electromagnetic parameters and temperature coupling model. Rotor self-inductance The critical range that varies with temperature can not only accurately identify the abrupt change point and linear stability range of inductance parameters as they drift with temperature, but also provide a quantitative basis for the adaptive switching of temperature compensation strategies. Furthermore, since the model simultaneously couples the temperature coefficient of the core permeability and the remanence of the permanent magnet, the electromagnetic parameter and temperature coupling model can more comprehensively reflect the variation law of inductance parameters under the combined action of multiple physical fields, thereby effectively improving the accuracy and robustness of inductance parameter temperature compensation.

[0240] The expression for the electromagnetic parameter-temperature coupling model is as follows:

[0241] ;

[0242] in:

[0243] For temperature-dependent stator-rotor mutual inductance, representing arbitrary temperature The magnetic coupling capability between the stator and rotor of the motor reflects the combined effect of temperature change on the magnetic coupling strength between the stator and rotor.

[0244] The rotor self-inductance is temperature-dependent, representing any temperature. The flux linkage of the rotor winding itself reflects the effect of temperature changes on the flux linkage of the rotor winding.

[0245] At this point, because the inductance parameters do not change completely linearly with temperature, nonlinear phenomena such as a sharp drop in permeability and irreversible demagnetization of permanent magnets can occur at extreme temperatures. Therefore, by using the rated reference temperature... The motor rotor mutual inductance Rotor self-inductance The mutual inductance of the motor rotor is calculated by combining electromagnetic parameters and temperature coupling model. Rotor self-inductance The critical range that varies with temperature can be determined not only by the temperature coefficient term in the electromagnetic parameter-temperature coupling model. , This allows for the precise characterization and quantification of the nonlinear trend of inductance parameters changing with temperature. Furthermore, by differentiating the model or solving for the extreme values ​​of the inductance rate of change by traversing the temperature range, it is possible to effectively identify and divide the critical temperature point and the stable compensation range, providing a reliable threshold basis for the subsequent switching of adaptive temperature compensation strategies.

[0246] However, because temperature fluctuations can cause synchronous changes in the core permeability and the remanence of the permanent magnet, this may lead to deviations in rotor mutual inductance and self-inductance from their rated reference values, and a decrease in the accuracy of flux linkage observation. Therefore, the mutual inductance of the motor rotor is... Rotor self-inductance The electromagnetic parameters and temperature coupling model are input as parameters, and the rotor mutual inductance is calculated using the electromagnetic parameters and temperature coupling model. Rotor self-inductance The corresponding fluctuation range is expressed as follows:

[0247] ;

[0248] in:

[0249] The fluctuation range of rotor mutual inductance represents the current internal temperature of the outdoor unit of the air conditioner. Below, rotor mutual inductance Relative to the rated reference temperature The relative rate of change of the lower reference value reflects the degree of influence of the combined change of the core permeability and the remanent magnetic density of the permanent magnet on the magnetic coupling capability of the stator and rotor. The larger the value, the more significant the drift of mutual inductance with temperature, and the greater the impact on the accuracy of rotor flux linkage observation.

[0250] The fluctuation amplitude of the rotor's self-inductance represents the current internal temperature of the outdoor unit of the air conditioner. Below, rotor mutual inductance Relative to the rated reference temperature The relative rate of change of the lower reference value reflects the degree of influence of the change in the core permeability on the flux linkage capability of the rotor winding itself. The larger the value, the more significant the drift of self-inductance with temperature, and the greater the impact on the stability of motor control.

[0251] The temperature coefficient of magnetic permeability of the iron core;

[0252] The temperature coefficient of remanence density of a permanent magnet;

[0253] This refers to the internal temperature of the outdoor unit of the air conditioner.

[0254] The rated reference temperature;

[0255] Because of rotor mutual inductance Rotor self-inductance The temperature sensitivity of the rotor can be quantitatively characterized through a coupling model of electromagnetic parameters and temperature. Therefore, the rotor mutual inductance can be derived by establishing a normalized mathematical relationship between inductance parameters and temperature coefficient. Rotor self-inductance The corresponding fluctuation range can not only intuitively quantify the degree of temperature disturbance to inductor parameters, but also improve the priority and strategy of parameter compensation, thereby achieving the effect of predicting the impact of parameter drift on control performance in advance. It can not only improve the anti-temperature interference capability of rotor flux observation, but also fully improve the operating stability and speed regulation accuracy of sensorless vector control system under variable temperature conditions.

[0256] Furthermore, due to rotor mutual inductance Rotor self-inductance The corresponding fluctuation amplitude can directly determine the boundary of flux linkage observation error and the adjustment range of the control strategy. At this time, the rotor mutual inductance is calculated by using the electromagnetic parameter and temperature coupling model respectively. Rotor self-inductance The corresponding fluctuation range can also be adaptively divided into temperature compensation thresholds and online tuned for control parameters, laying the foundation for subsequent dynamic adjustment of compensation strategies and optimization of controller parameters.

[0257] Furthermore, due to rotor mutual inductance Rotor self-inductance The electromagnetic properties of an air conditioner change nonlinearly with temperature, while the internal temperature of the outdoor unit of the air conditioner... These are the core environmental parameters affecting its characteristics. At this point, the actual value of the inductance parameter will deviate from the rated reference value. Therefore, the rotor mutual inductance is calculated using a coupling model of electromagnetic parameters and temperature. Rotor self-inductance Corresponding fluctuation range and This can represent the degree of deviation of inductance parameters from their changes with temperature. The changing state of the motor's electromagnetic characteristics under current operating conditions facilitates subsequent analysis of the internal temperature of the air conditioner's outdoor unit. Filter out the corresponding fluctuation range;

[0258] And due to the internal temperature of the air conditioner outdoor unit during defrosting. The inductance parameters fluctuate in a dynamic and fluctuating state (due to heat absorption during frost melting and alternating effects of refrigerant heat flow). and It will also exhibit nonlinear oscillations with temperature changes; if the fluctuation amplitude calculated in a single instance is used directly... and Parameter compensation is prone to deviation due to instantaneous temperature fluctuations, which can affect the rotor flux linkage component. , The occurrence of problems such as inaccurate observations necessitates setting an iteration threshold. The iteration calculation stops when the iteration count equals the iteration threshold, and the same number of fluctuation amplitudes as the iteration threshold are obtained.

[0259] The maximum and minimum values ​​among multiple fluctuation amplitudes are selected from the iteration number threshold to form a temperature threshold. Specifically, the maximum value is the upper limit of the temperature threshold, and the minimum value is the lower limit of the temperature threshold.

[0260] The specific rules for setting the iteration number threshold are as follows:

[0261] Due to rotor mutual inductance Rotor self-inductance The corresponding fluctuation ranges and It directly determines the control accuracy of the compressor motor; if the fluctuation range... and Exceeding the allowable range will cause the rotor flux component to... , Increased calculation deviation and reduced calculation accuracy consequently affect the calculation of the motor rotor position. and the real-time speed of the motor rotor There was a discrepancy, therefore, by obtaining the internal temperature of different air conditioner outdoor units... The corresponding fluctuation range , Samples, and the internal temperature of the outdoor unit of the air conditioner when the air conditioner is in defrost mode. Fluctuation period and rotor mutual inductance Rotor self-inductance The sampling period will determine the internal temperature of the air conditioner outdoor unit. The fluctuation period divided by the rotor mutual inductance Rotor self-inductance The calculation result obtained from the sampling period is rounded up to the integer, thereby setting the threshold for the number of iterations;

[0262] Therefore, by setting a threshold for the number of iterations, the temperature threshold can be precisely matched with the temperature characteristics of the motor inductance parameters, improving the operating condition adaptability of the temperature threshold and facilitating subsequent comparison between the temperature threshold and instantaneous deviations. It outputs a precise temperature compensation benchmark.

[0263] Because the temperature-compensated inductance parameters still exhibit dynamic coupling with the motor speed and stator current, residual deviations between the observed and actual flux linkage values ​​may still occur. However, since the baseline error of the inductance parameters has been corrected through temperature compensation, the proportion of coupling error will be significantly reduced, and the convergence of flux linkage observations will be greatly improved. Therefore, it is necessary to combine the temperature-compensated actual inductance parameters with the observed stator flux linkage and current values ​​to accurately calculate the rotor flux linkage component. , Motor rotor position and the real-time speed of the motor rotor This enables it to accurately track the dynamic changes of the rotor flux under variable temperature conditions, which not only suppresses the observation errors caused by temperature drift and parameter coupling, but also effectively improves the stability of compressor operation and the heating stability under air conditioning defrosting conditions.

[0264] Calculate rotor flux components , The specific expression is as follows:

[0265] ;

[0266] ;

[0267] in:

[0268] This represents the true value of the rotor's self-inductance under the current internal temperature of the outdoor unit of the air conditioner.

[0269] This represents the true value of the mutual inductance between the stator and rotor at the current internal temperature of the outdoor unit of the air conditioner.

[0270] For the self-sensing of the stator, , These are the stator flux linkage components in the α and β phase stationary coordinate systems, respectively;

[0271] , These are the stator current components in the α and β phase stationary coordinate systems, respectively;

[0272] Because of the rotor flux component , With respect to the position of the motor rotor Real-time rotational speed of motor rotor There is a clear geometric mapping relationship, so the rotor flux vector can be calculated for angle and angular velocity using an arctangent function or a phase-locked loop observer, enabling real-time estimation of rotor position and speed. Furthermore, closed-loop correction using temperature-compensated inductance parameters and flux observations effectively suppresses parameter drift and coupling interference, ensuring sufficient accuracy in rotor position and speed estimation. Moreover, when the system detects changes in the actual heating load (such as the deviation between the set indoor temperature and the actual temperature) or compressor operating conditions (such as pressure and current fluctuations), the calculated motor rotor position is adjusted using a dual closed-loop controller for both speed and current. and the real-time speed of the motor rotor As a feedback input, the corresponding d-axis and q-axis current commands are output, and the d-axis and q-axis current commands are converted into three-phase drive signals through space vector pulse width modulation to drive the compressor to run.

[0273] During compressor operation, real-time data on the three-phase stator voltage and current of the compressor motor are collected, combined with previously observed rotor position data. and the real-time speed of the motor rotor The actual output effect of the d-axis and q-axis current commands is verified in reverse. By comparing the deviation between the actual load demand and the current operating parameters through the closed-loop controller, the d-axis and q-axis current commands are dynamically corrected, while the rotor flux component is adjusted. , , the internal temperature of the air conditioner outdoor unit The real-time changes are fed back to the temperature compensation and inductance parameter dynamic correction module 200, which adjusts the Clark transformation and Park transformation coefficients in real time to ensure that the compressor can maintain a stable speed and accurate torque output during the defrosting stage of the air conditioner. This avoids pressure and current fluctuations in the sensorless vector control system and frequent compressor start-stop, thus maintaining continuous indoor heating and improving the user experience.

[0274] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A variable frequency heat pump intelligent control system based on sensorless vector control, characterized in that: It includes a sensorless vector control model construction and rotor state observation module (100), a temperature compensation and inductance parameter dynamic correction module (200), and a compensation benchmark adaptive switching and iterative optimization module (300). The sensorless vector control model is constructed and the rotor state observation module (100) obtains the three-phase stator voltage and current of the compressor motor, and obtains the inductance parameters through the DC bias method to construct a sensorless vector control model for decoupling the compressor motor torque and flux linkage and eliminating parameter interference; the inductance parameters include rotor mutual inductance and rotor self-inductance. Input the three-phase stator voltage and current to the sensorless vector control model, and output the compressor motor rotor position and the real-time speed of the motor rotor. The temperature compensation and inductance parameter dynamic correction module (200) calculates the motor winding resistance based on the motor stator phase voltage and phase current, and derives the real-time motor winding temperature. Based on the real-time temperature of the motor windings, the internal temperature of the outdoor unit of the air conditioner is calculated as a temperature compensation benchmark; then the changes in rotor mutual inductance and rotor self-inductance are calculated to obtain new rotor mutual inductance and rotor self-inductance. Input the new rotor mutual inductance and rotor self-inductance into the sensorless vector control model, and recalculate the rotor flux component, motor rotor position, and motor rotor real-time speed. The adaptive switching and iterative optimization module (300) of the compensation benchmark obtains the instantaneous deviation, sets the temperature threshold and the iteration number threshold; compares the temperature threshold and the instantaneous deviation, outputs different types of temperature compensation benchmarks, and recalculates the rotor flux component, motor rotor position and motor rotor real-time speed again through the sensorless vector control model based on the different types of temperature compensation benchmarks.

2. The intelligent control system for a variable frequency heat pump based on sensorless vector control according to claim 1, characterized in that: The sensorless vector control model construction and rotor state observation module (100) specifically constructs the sensorless vector control model as follows: Based on the three-phase stator voltage and current of the motor, a three-phase voltage balance equation is constructed to describe the dynamic balance relationship between stator voltage, current and flux linkage. Using equal power transformation, a Clark transformation matrix is ​​constructed from three-phase to two-phase. The three-phase stator voltage and current are substituted into the Clark transformation matrix to calculate the α-axis components and β-axis components, and an α and β two-phase stationary coordinate system is constructed. By using the orthogonal linear transformation of the Clark transformation matrix, the three-phase stator voltage and current are directly converted into two-phase stationary components in the α and β coordinate systems, thus removing the spatial coupling relationship of the three-phase windings. The Park transformation converts the two-phase stationary components of the α and β coordinate systems into d and q rotating coordinate system components for decoupling control of flux linkage and torque.

3. The intelligent control system for a variable frequency heat pump based on sensorless vector control according to claim 1, characterized in that: In the temperature compensation and inductance parameter dynamic correction module (200), the motor winding resistance is equal to the sum of the active power of the three-phase stator voltage and current, divided by the sum of the mean square values ​​of the three-phase stator current. The real-time temperature of the motor winding is equal to the rated reference temperature plus the difference between the motor winding resistance and the motor winding resistance at the rated reference temperature, divided by the product of the resistance temperature coefficient of the copper winding and the winding resistance at the rated reference temperature. The internal temperature of the outdoor unit of the air conditioner is equal to the real-time temperature of the motor windings plus the instantaneous deviation between the real-time temperature of the motor windings and the ambient temperature inside the outdoor unit, plus the real-time temperature of the motor windings.

4. The intelligent control system for a variable frequency heat pump based on sensorless vector control according to claim 1, characterized in that: The temperature threshold rules set in the compensation benchmark adaptive switching and iterative optimization module (300) are as follows: Obtain the temperature coefficients of core permeability and permanent magnet remanent density corresponding to the mutual inductance and self-inductance of the motor rotor, and calculate the fluctuation amplitudes of the mutual inductance and self-inductance of the motor rotor as a function of temperature. Obtain the fluctuation amplitudes corresponding to rotor mutual inductance and rotor self-inductance respectively, and then iteratively calculate the fluctuation amplitudes again; Set an iteration count threshold, and stop iterating when the iteration count equals the iteration count threshold, and obtain the same number of fluctuation amplitudes as the iteration count threshold; The maximum and minimum values ​​among multiple fluctuation ranges are used to form the temperature threshold. Specifically, the maximum value is the upper limit of the temperature threshold, and the minimum value is the lower limit of the temperature threshold.

5. The intelligent control system for a variable frequency heat pump based on sensorless vector control according to claim 4, characterized in that: The iteration number threshold rule set in the compensation benchmark adaptive switching and iterative optimization module (300) is as follows: Samples of fluctuation amplitudes corresponding to different internal temperatures of the outdoor unit of the air conditioner are obtained. When the air conditioner is in defrost mode, the fluctuation period of the internal temperature of the outdoor unit of the air conditioner, as well as the sampling period of rotor mutual inductance and rotor self-inductance are obtained. The calculation result obtained by dividing the fluctuation period of the internal temperature of the outdoor unit of the air conditioner by the sampling period of rotor mutual inductance and rotor self-inductance is rounded up to the integer, thereby setting the threshold for the number of iterations.

6. The intelligent control system for a variable frequency heat pump based on sensorless vector control according to claim 4, characterized in that: The specific comparison between the temperature threshold and instantaneous deviation in the compensation benchmark adaptive switching and iterative optimization module (300) is as follows: like If the temperature threshold is reached, the currently calculated internal temperature of the outdoor unit of the air conditioner will be used as the temperature compensation benchmark to recalculate the new rotor mutual inductance, rotor self-inductance, and rotor flux component. Conversely, if the instantaneous deviation is less than or equal to the temperature threshold, the real-time temperature of the motor windings will be used as the temperature compensation benchmark again to recalculate the new rotor mutual inductance, rotor self-inductance, and rotor flux linkage components.

7. The intelligent control system for a variable frequency heat pump based on sensorless vector control according to claim 1, characterized in that: The rotor flux component is calculated in the sensorless vector control model as follows: ； in: This refers to the stator winding resistance. The rotor's electric angular velocity; For mutual inductance between stator and rotor; For rotor self-inductance; , These are the components of the stator voltage in the α and β coordinate systems; , These are the components of the stator current in the α and β coordinate systems; This is the integration operator.

8. The intelligent control system for a variable frequency heat pump based on sensorless vector control according to claim 1, characterized in that: In the temperature compensation and inductance parameter dynamic correction module (200), based on the internal temperature of the outdoor unit of the air conditioner, the changes in rotor mutual inductance and rotor self-inductance in the sensorless vector control model are calculated as follows: The new rotor mutual inductance is the rotor mutual inductance plus the change in rotor mutual inductance at the current internal temperature of the outdoor unit of the air conditioner. The new rotor self-inductance is the rotor self-inductance plus the change in rotor self-inductance at the current internal temperature of the outdoor unit of the air conditioner.

9. The intelligent control system for a variable frequency heat pump based on sensorless vector control according to claim 1, characterized in that: The change in rotor mutual inductance: ； The change in rotor self-inductance: ; in, The temperature coefficient of magnetic permeability of the iron core. is the temperature coefficient of remanence density of a permanent magnet.

10. The intelligent control system for a variable frequency heat pump based on sensorless vector control according to claim 7, characterized in that: The rotor flux linkage component is recalculated in the temperature compensation and inductance parameter dynamic correction module (200) as follows: ； ； in: This represents the true value of the rotor's self-inductance under the current internal temperature of the outdoor unit of the air conditioner. This represents the true value of the mutual inductance between the stator and rotor at the current internal temperature of the outdoor unit of the air conditioner. For the self-sensing of the stator, , These are the stator flux linkage components in the α and β phase stationary coordinate systems, respectively; , These are the stator current components in the α and β phase stationary coordinate systems, respectively.

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